Carbon electrode for electric furnaces.



B. REDLICH. v

CARBON ELECTRODE FOR ELECTRIC FURNACES.

APPLICATION FILED FEB.19,1912.

1,048,581, Patented Dec. 31, 1912.

Inventor .llttorney.

UNITED STATES PATENT OFFICE.

BERTHOLD BEDLICH, OF RATIBOR, GERMANY, ASSIGNOR TO THE FIRllI OF PIJANIA- WERKE AKTIENGESELLSCHAF'I FIIR KGHLENFABRIKATICN, OF RATIBOR, GER- MANY.

To all whom it may concern:

Be it known'that L/BER'IHOLD Rrlnuon,

subject of the Emperor-mf Austria-Hungary, residing at Ratibor, Upper Silesia, Germany, doctor'of chemistry,-have invent-jed certainnewrandiise ful Improvements in electrical resistanceare embedded offer various difficulties "inf theirv production r If the metal core is iiise'rtcd intothe carbon elec t-rcde before burning, theljmetal', especially.

iron, absorbs carbon during theburning process and thus becomes brittle, so that its mechanical durability, which is 'of-importanee when it. is iniuse is influenced. If the core isinserted into-the 'hollow spaces or recesses, proyidedjkin the" electrode, after burning theproduction'of 'a sufficiently secure contact Ion the Qemployment"cheery simple and marketable c'rossseetions, .ott'ers difficulties; Experiments haveproved that.

a good contact between the metal core and the electrode is obtained-by casting molten metal ormetalalloysinto the hollow spaces provided the electrode, If. in this manner" great advantages are. obtained. dideulties are still met with, as the metal contracts on solidification and the carbon retains its shape, so that the metal core after solidification may be separated from the electrode by a thin air space thus producing a bad contact between the metal core and the carbon electrode. This disadvantage can be avoided by providing the metal core and the bore in the carbon of a corresponding form and employing the property of the solidifying: metal or metal alloys, which contract to a high degice, for the purpose of effecting a firm pressing of the metal core against the electrode wall. The form of the. metal core can also be so chosen that, after casting it can be made to fit accurately into the form of the hollow space by suitable mechanical auxiliary means.

In the drawing are shown a few c n l uc- Specification of Letters Patent.

CARBON ELECTRODE FOR ELECTRIC FURNACES.

Patented Dec. 31, 1912.

Application filed February 19, 1912. Serial N 0. 678,603.

plan and Figs '5 and 6 show further modi-. i'ications with corresponding plans.

Fig. 1 showsthe carbon electrode WhlCh ,is

provided with a conical bore.,.The metal.

core b whichhas been cast intothis is by reason of the end plate a firmly-pressed against the inner walls of the carbon on solidification. According to Fig. 2, a metal eore-b is loosely inserted into the carbonelectrode' 0.. T he bore of the carbon electrodeinwthis instance isfalsoconical andbetweenthe inner wall of the carbon and the metal .cor I) a metal ormetal alloy is cast. which on solidification forms a good contact between the hollow body and the core due to'its contraction.

In Fig.3 the metal core I) is prbvided-of a slight conical form at both ends. After pouring in the castmass, the metal contracts both in a longitudinal andina transverse direction. I In this manner a high pressure is exerted in the direction of the arrows and the metal shrinks firmly against the wall of the carbon electrode. It is advisable to provide these walls withgrooves forthe purpose of increasing the contact surface.

In Fig. 4 the metal core is of cylindrical -form but its ends are conical and terminate in cylindrical or rectangular portions. Also in this case, an adhesion of the metal core along the conical surfaces as also at the end castings takes place. This arrangement simultaneously operates as the armature for the electrode, as a strong pulling action takes place in the direction of the arrows.

Fig. 5 shows a constructional form in which the metal core is pressed into the hollow space provided in the body of the carbon by mechanical means. The metal core I) is of slightly conical form and into its end is cast a screw-bolt a. After casting, there is inserted in the recess 7. provided at the other end of the electrode. a strong washer h and on this a nutf. If. on casting. the core has shrunk, and an air space has been formed between the metal core and the elcctrode. an intimate contactwith the walls of the electrode is effected by a powerful tightening: of the nut fon the bolt.

Fig. 6 shows the same principle in another arrangement. On the employment of the electrode care must be taken that the coni al responding plan. Fig. 4 is a cr ss section I part of the core in which the bolt is secured o another mod fication and a corresponding i 15 CODtmIIQlII dIrQCtGd upward.

By the heat which is produced in the electric furnace the metal core expands more than the carbon, and therefore also during the employment of the electrode a firm pressing and thus also a good contact 15 efi'eeted between the metal core and the electrode.

' What Lclaim as my invention and desire to secureby Letters Patentisi 1. A carbon electrode for electric furnaces consistingof a carbon member having a hole, means for reducing the electrical resistance of the carbon member comprising a metal core insaidhole said metal core extending along the' whole length ofthe electrode andb'emg retained in intimate contact fli' th ar on m mbe 21A carbon electrode for electric furnaces comprising a carbon member, means'for reducingtheelectrical resistance of the carbon member, consisting of a metal core cast and shrunk into the carbon member, said metal core extending along the whole length of the carbon member. I

3IA arboh electrode for electric furnaces compr' ng a carbon-member, means for redu'cingthe electrical resistance of the carbon memberficonsisting of a-metal core cast and shrunk' iii'to the carbon member, said metal core extending along the whole length of the carbon member, and means for retaining the core in said carbon member.

4. A carbon electrode for electric furnaces comprising a carbon member having a hole,

means for reducing the electrical resistance of such form that the core on solidification will shrink into said hole and firmly contact with the carbon member.

5. A carbon electrode for electrical purposes comprising a carbon member having a hole, said hole extending along the whole length of the carbon member and being partly conical, means for reducing the electrical resistance of the carbon member consisting of a metal core, cast into the hole and on solidification contracting and firmly contacting with the carbon member.

In testimony whereof I have hereunto signed my name to this specification, in the presence of two subscribing witnesses.

" BERTHOLD REDLICH.

Witnesses:

FRANK G. Po'rrs, ERNST KATZ.

Copies of tlflspatent may be obtained or five cents each, by addressing the Commissioner of Patents r Washington, D. C." 

